Current techniques for treating intraocular tumors unavoidably damage surrounding healthy eye tissue with equivocal destruction of the neoplasm. This can cause severe visual loss or the enucleation of several thousand eyes yearly in the United States. With malignant tumors, trauma during treatment has been implicated in the metatastic seeding to other parts of the body. The purpose of the proposed project is to develop a carbon dioxide laser vaporization system that will safely and effectively obliterate retinal and choroidalintraocular tumors with excellent hemostasis and total vaporization of the tumor tissue. Healthy ocular tissue will be spared, to better preserve vision, and to obviate the need for enucleation. In cases of malignant tumors, it is projected that CO2 laser vaporization will prove to be less traumatic and provide a longer patient survival rate than current techniques. We have developed a delivery system to channel the carbon dioxide laser radiation to tumor masses within the eye. Laser power will be accurately monitored and specialized safety interlocks will be inclued. A flow nitrogen system will perfuse the vitreous cavity during laser treatment, allowing rapid removal of vaporized tumor tissue. The entire CO2 laser system is under construction at S.R.I. International in Palo Alto, CA, with projected delivery in December 1978. Animal histological studies will be performed initially, to quantitate exactly the tissue effect of various carbon dioxide laser radiation modes in specific areas of the eye. When the precise parameters for safe, effective CO2 laser radiation have been established, the clinical phase will begin. Extraocular and intraocular tumors will be vaporized, with an emphasis on neoplasms. The results will be evaluated through detailed biostatistical analysis. Patients will be followed for a minimum of five years.